Save user application data in database after login

I’m trying to use the express-opened-connect library to authenticate my application.

I can get logged in and access the user data but am having trouble finding out where to make the creation of a User object in my database using this info.

Ideally, I would think checking the DB after login for a user that is the same as the logged in one and creating a new one if it doesn’t exist would work. But where would I add such functionality? I only want it to run after someone logs in.